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Balancing FM Systems. BATOD March 2013 Colin Peake Educational Audiologist South of England Cochlear Implant Centre.

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Presentation on theme: "Balancing FM Systems. BATOD March 2013 Colin Peake Educational Audiologist South of England Cochlear Implant Centre."— Presentation transcript:

1 Balancing FM Systems. BATOD March 2013 Colin Peake Educational Audiologist South of England Cochlear Implant Centre

2 Two Questions …… Why Use Personal FM Systems? What is the purpose of balancing FM Systems? Balancing FM systems. BATOD March '13

3 Why Use Personal FM Systems FM AUDITORY TRAINING SYSTEMS. Characteristics, Selection, and Use. Ross, 1991

4 Balancing FM systems. BATOD March '13 Why Use Personal FM Systems? “How long would you listen to a lecture that you couldn’t quite hear? How long would you strain to hear the words of a speaker at a conference? How much effort, self-discipline, and focused concentration are you, as an adult and competent learner, willing to put into a group listening situation……?

5 Why Use Personal FM Systems? …….Perhaps the most critical question is, why are we surprised when many young children appear distracted, unfocused, undisciplined, and overwhelmed by the demands of classroom listening?” Carol Flexer in, FM AUDITORY TRAINING SYSTEMS. Characteristics, Selection, and Use. - Ross, 1991, Balancing FM systems. BATOD March '13

6 Why Use Personal FM Systems? The ability to discriminate individual phonemes, to hear words/sound differences, is defined as intelligibility, as distinguished from audibility, which is the ability to detect the presence of speech. If because of hearing loss, poor classroom acoustics, and/or poor attending skills, a child cannot discriminate wave from raise, for example, he or she will not learn appropriate semantic distinctions unless deliberate intervention occurs. Carol Flexer in, FM AUDITORY TRAINING SYSTEMS. Characteristics, Selection, and Use. Ross, 1991, Balancing FM systems. BATOD March '13

7 Why Use Personal FM Systems? “The purpose of using technology is to promote the child’s right to hear and to benefit from educational instruction.” Carol Flexer in, FM AUDITORY TRAINING SYSTEMS. Characteristics, Selection, and Use. Ross, 1991,

8 Balancing FM systems. BATOD March '13

9 Kimberly Balancing FM systems. BATOD March '13

10 What is the purpose of balancing FM Systems? To ensure that the level and quality of sound a child hears through the FM Systems microphone matches what he hears through the hearing instrument’s microphone. Balancing FM systems. BATOD March '13

11 Importance of Level Too High –Serious risk of distortion –Danger of Compression Too Low –Makes little difference to the child –Denied the right to access and benefit from instruction –Waste of resource –Disenchantment Balancing FM systems. BATOD March '13

12 Importance of Quality Frequency response curves Balancing FM systems. BATOD March '13 Frequency response curves for Medel Opus 2 (curve #1 @ 60 dB and with CA Digisystem (curve#2 @ 65 dB

13 When Should Balancing be Done At initial fitting Change of hearing instrument Change of FM system Disturbance of controls Balancing FM systems. BATOD March '13

14 Good Practice Fitting Procedure  Listening check of speech processor and FM system where possible, adjust settings.  An objective test-box method for setting up levels (see Quality Standards and Good Practice Guidelines)  Validate the settings with a speech test (eg McCormick) or  Validate the settings with a speech in noise test

15 But, what if a child can’t do a speech test? May have poor discrimination years after implantation May not co-operate due to –tiredness –immaturity –language difficulties –behavioural difficulties Balancing FM systems. BATOD March '13

16 Callum Balancing FM systems. BATOD March '13

17 Other Inputs Applied to FM Transmitters Output from –Television. –CD player, other audio devices –Computer/Whiteboard –Soundfield device. Balancing FM systems. BATOD March '13

18 Other Inputs Applied to FM Transmitters Television, CD player, other audio devices, computer/ whiteboard. All should be used with caution – only on children who can report accurately. Soundfield systems. Used in the context of learning so must be balanced. Balancing FM systems. BATOD March '13

19 Balancing Soundfield Systems Obtain FR curve for hearing instrument Obtain FR curve for FM system and adjust volume so curves match Set FM transmitter to re-broadcast, place soundfield emitter in the test box – lid open. Obtain frequency response curve and adjust output of soundfield system so curves match. Balancing FM systems. BATOD March '13

20 Demonstration Re-broadcasting.avi Balancing FM systems. BATOD March '13

21 Any further enquiries to: c.peake@soton.ac.uk Balancing FM systems. BATOD March '13


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